Ammonia, Nitrite, Nitrate and Chlorine are the four water parameters that matter here. Many people consider them all powerful poisons for fish. In reality, only chlorine is a powerful poison for fish.
The many myths about ammonia, nitrite, nitrate, and chlorine are:
- Nitrates going above 10, 20, 40 or even 80 ppm will shorten the life of an adult fish.
- Long term ammonia levels at some level below 5 ppm or nitrite levels below 1 ppm at a pH of 7 and a temperature of 28°C. (82°F.) decrease the life expectancy of fish because of toxicity.
- Short term ammonia levels at 5 to 10 ppm or nitrite levels at 1 ppm to 5 pm are very toxic to fish at a pH of 7 and will kill the fish rapidly.
- When a lot of fish die overnight after a water change it is typically due to ammonia, not a chlorine pulse, low oxygen or high carbon dioxide.
- The standard dose of conditioner will remove even heavy chlorine or chloramine levels.
- There are chlorine water conditioners such as Prime which “neutralize” ammonia, nitrite, and “toxins”.
- It is important to test your water frequently with test kits such as API Master test Kit, Nutrafin Test Kit, Tetra easy strips, Sera Aquatest, API 5 in 1 Test Strips, or the Fluval Water test Kit.
All these myths are simply false.
Toxic Levels
Acute toxicity is when fish die within hours or days. This is the “toxic” level in the table below. Chronic toxicity is where the fish will have diseases and a general “failure to thrive.” This is the “Alarm” level below.
The levels are as follows:
| pH van het water | API Ammoniaktest in ppm | API Nitriettest in ppm | |||
|---|---|---|---|---|---|
| pH | Waarschuwing | Alarm | Giftig | Alarm | Giftig |
| 6.6 pH | 16 | 64 | 160 | 0.5 | 2 |
| 6.8 pH | 11 | 44 | 110 | 0.5 | 2 |
| 7.0 pH | 8 | 32 | 80 | 1 | 4 |
| 7.2 pH | 5 | 20 | 50 | 1.5 | 6 |
| 7.4 pH | 3 | 12 | 30 | 2 | 8 |
| 7.6 pH | 2 | 8 | 20 | 2 | 8 |
| 7.8 pH | 1 | 4 | 10 | 2.5 | 10 |
| 8.0 pH | 0.8 | 3 | 8 | 3 | 12 |
| 8.2 pH | 0.6 | 2 | 6 | 3.5 | 14 |
| 8.4 pH | 0.4 | 2 | 4 | 3.5 | 14 |
| 8.6 pH | 0.25 | 1 | 2 | 4 | 16 |
| Nitraat Alarm Niveau is hoger dan 80 PPM | |||||
| Nitraat Giftig Niveau is hoger dan 440 PPM | |||||
To read the ammonia and nitrite values in this table, first find the pH of the aquarium. Then find that pH in the left column. Read about the levels the API tests will show. Green is the “Alarm” level where more testing is needed, yellow is the “Alarm” level where one should perform a 50% water change. And “Toxic” is the level where one needs to do a 75% water change. Note that many of these levels require diluting the aquarium water with 9 parts distilled water. Test the diluted water. Multiply the results by ten and you have the levels in the aquarium.
The figures for the toxicity of ammonia, nitrite and nitrate will come as a shock to most experienced hobbyists. But the figures are supported by much research by universities. The ammonia levels are what Seachem outlines. They are solid. Ammonia, nitrite and nitrate are not as toxic as we all believe.
In general fish from lakes or ponds have a higher tolerance for nitrogen compounds than do fish from rivers.
Note that all hobbyists should have aquariums with zero ammonia and zero nitrite after a few months. The reason behind zero ammonia and zero nitrites has nothing to do with the toxicity of ammonia or nitrite. It has to do with the number of bacteria in the water.
If one has amounts of ammonia or nitrite, there is probably not adequate biofiltration in the aquarium. And if one does not have adequate biofiltration, one is likely to have high bacteria counts in the water. And high bacteria counts (i.e., “dull” or murky water) are very detrimental to the long-term health of the fish.
It should be emphasized that it takes time to achieve this. An aquarium must be set up for three or four months before this goal can be achieved, even with huge amounts of filter surface area. And it should be emphasized that in the meantime, short excursions to 5 ppm ammonia, 2 ppm nitrite and 880 ppm nitrate or even higher at a pH of 7.0 will not harm the fish.
Chlorine is toxic in very small amounts, on the order of 0.05 ppm chlorine. Chlorine is a very bad player. The reason for this is simple. Free chlorine gas does not occur in nature. Ammonia, nitrite and nitrate all occur in nature. In the case of a lake with lots of organic matter, the levels of the three nitrogen compounds can become surprisingly high. So Mother Nature has provided most fish with coping mechanisms for these three naturally occurring nitrogen compounds. Nature has provided no such coping mechanism for chlorine.
Testing the Water Parameters
On social media, you constantly hear the question: what are your water values? That is, what are your ammonia, nitrite and nitrate levels? And this supposedly gives a clear picture of whatever disease the fish has. This is simply nonsense. There is simply no way to determine from water parameters what disease a fish has.
A related myth is that it is somehow important to test your water regularly with test kits such as API Master test Kit, Nutrafin Test Kit, Tetra easy strips, Sera Aquatest, API 5 in 1 Test Strips, or the Fluval Water test Kit. This makes a lot of money for many test kit manufacturers, but for most aquarium hobbyists it doesn’t make a lot of money. People end up getting obsessed with it. The ONLY time I use a test kit is when I need to turn an aquarium in quickly for whatever reason. And even then, it’s probably just not necessary.
Further Research
If one is more interested in the science behind all this simply read the following links:
5.2. Safe ammonia levels
5.3. Safe Nitrite Levels
5.4. Safe Nitrate Levels
5.5. Chlorine and Chloramine
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Startpage Aquariumscience
Source: Aquariumscience.org – David Bogert
The author, David Bogert, is a certified chemist, something that is only useful in the sections on chemicals such as conditioners and fertilizers. He has about 43 patents, mostly in the medical device field, which only helps with some DIY designs. But he also spent much of his life as a scientific researcher working on literature research, data analysis, statistics, and a little-understood field called “experimental design.” This experience is very applicable to ALL fishkeeping science. The author has been keeping all kinds of aquariums and all kinds of fish for over 54 years. He currently has ten large and many small aquariums. But note that he is not an “expert” in all aspects of aquarium keeping. The ecology of an aquarium is far too complex for anyone to be a true “expert” in all the different aspects. One can only search the journals and books for relevant research in each individual subject.
